1. Field of the Invention
The present invention is directed to a gel composition containing at least one cosmetic and/or dermatological active agent, at least one electrolyte, cetylhydroxyethyl cellulose and water useful for treating the skin, scalp, hair, mucous membranes and/or nails.
2. Discussion of the Background
Topical compositions in the form of an aqueous gel or emulsion are well-known in the cosmetic, dermatological and pharmaceutical fields. These compositions contain gelling agents which impart consistency and stability to the gel. Most of the gelling agents currently used are carboxyvinyl polymers, which are neutralized with a base. However, some materials cannot be used in these compositions because they are incompatible with carboxyvinyl polymer gelling agents. For example, electrolytes, i.e., inorganic or organic salts, are incompatible with neutralized carboxyvinyl polymers because they "break" the emulsion and liquefy it. As a result, these compositions have an unsightly appearance.
Electrolytes are particularly desirable components of thickened, topical gel compositions when they have a beneficial effect on the skin or hair and are used in combination with cosmetic and/or dermatological active agents. Electrolytes are particularly useful in gel compositions where the active agents have an irritant side effect when applied alone because they may reduce the irritating nature of these active agents. The gelling agent should be compatible with the electrolytes while preserving the efficacy of the active agent and the electrolytes. In addition, gel compositions for topical application are preferably clear and stable.
Polysaccharide-type gelling agents, such as guar gums, xanthan gums and cellulose derivatives, have been used in place of carboxyvinyl polymers. EP-A-654270 describes a topical composition intended for the treatment of acne and seborrhoeic dermatitis containing a mixture of salts and hydroxyethyl cellulose as the gelling agent. However, these compositions, especially aqueous gels containing no oily phase, have an unsightly lumpy appearance. In addition, they leave the skin "wet looking" after application because these compositions do not penetrate sufficiently into the skin. Therefore, these materials have limited use as cosmetics and/or dermatological agents, where product appearance is critical. The combination of these cellulose derivatives with another thickening agent, such as a silicate as described in WO-A-93/8230, provides compositions with the same disadvantages.
Seifen, Ole, Fette, Wachse Journal, vol. 120, No. 15, 1994 describes the use of hydrophobically modified hydroxyethyl cellulose in compositions for skin care and the compatibility of this material with various types of salts. However, these compositions do not contain cosmetic active agents. In addition, there is no suggestion of a clear and stable gel composition containing cetylhydroxyethyl cellulose, active agents and a large quantity of electrolyte.
Therefore, the need remains for gel compositions which overcome the disadvantages of known gelling agents: lack of consistency, instability, lumpy appearance, unpleasant sensation to the touch and incompatibility with electrolytes.
The present Applicants have now unexpectedly found that cetylhydroxyethyl cellulose stabilizes gel compositions containing active agents and large quantities of electrolyte.